When it comes to Mutually Assured Destruction (MAD), you have to use the only thing the Muslims care about - their doctrine:
Just say, "Dear Muslim community. We know that most of the attacks on us come from a deep-seating historical belief that we shouldn't exist. According to the ideology (Islam) that you hold most dear, and take most seriously, we shouldn't exist as a religion or a culture - never to rule anyone. Iran keeps trying to get nuclear weapons. We already have them. So we'll make this simple. If you launch a nuclear attack on us, you'll cause a lot of damage to us. It will be horrible. It might be the end of us as a nation. However, we have our nuclear weapons pointed at the only thing you hold dear - all of your holy sites. If we go, Mecca goes. Yes, we know that's in Saudi Arabia. But this is not national, its ideological. So your most holy place in the world - poof! Its atoms are spread across the countryside, along with everyone there. That would be horrible, but if you are willing to nuke us, we have to be willing to nuke you in ways that honestly hurt you and your radical world view. The well that 12th Imam should crawl out of at the end of time, nuked. Kabba, gone. Every mosque from here to Istanbul will be wiped off the map, including the one in Jerusalem. Imagine all those required pilgrimages to Mecca all Muslims should make when the entire area is covered in radioactive glass. Now Govern yourself accordingly."